Oxidation resistance of Ti ₃ AlC ₂ and Ti ₃ Al _0.8 Sn _0.2 C ₂ MAX phases: A comparison

Abstract

Abstract Ti 3 AlC 2 and Ti 3 Al 0.8 Sn 0.2 C 2 MAX phase powders are densified using Spark Plasma Sintering (SPS) technique to obtain dense bulk materials. Oxidation tests are then performed over the temperature range 800°C‐1000°C under synthetic air on the two different materials in order to compare their oxidation resistance. It is demonstrated that, in the case of the Ti 3 Al 0.8 Sn 0.2 C 2 solid solution, the oxide layers consist in TiO 2 , Al 2 O 3 , and SnO 2 . The presence of Sn atoms in the A planes of the solid solution leads to an easy diffusion of Sn out of the MAX phase which promote the formation of the nonprotective and fast growing SnO 2 oxide. Moreover, the small Al/Ti atom's ratio promotes the growth of a nonprotective rutile‐TiO 2 scale as well. In the case of the Ti 3 AlC 2 MAX phase, the oxide layer consists in a protective alumina scale; a few TiO 2 grains being observed on the top of the Al 2 O 3 layer. The parabolic oxidation rate constants are about 3 orders of magnitude smaller for Ti 3 AlC 2 compared to Ti 3 Al 0.8 Sn 0.2 C 2 .